Decrease of invasive pneumococcal disease (IPD) in adults after introduction of pneumococcal 13-valent conjugate vaccine in Spain.

Jordi Càmara,Carmen Ardanuy,Nieves Larrosa,José María Marimón,María Dolores Quesada,Emilio Pérez-Trallero,Josefina Liñares,Meritxell Cubero,Asunción Fenoll,Emilia Cercenado,Dionísia Fontanals

doi:10.1371/journal.pone.0175224

Abstract

A prospective laboratory-based multicenter study that collected all adult invasive pneumococcal disease (IPD) episodes from 6 Spanish hospitals before (2008–2009) and after (2012–2013). The 13-valent pneumococcal conjugate vaccine (PCV13) licensure was conducted in order to analyze the impact of PCV13 introduction for children on adult IPD. A total of 1558 IPD episodes were detected. The incidence of IPD decreased significantly in the second period by -33.9% (95% CI, -40.3% to -26.8%). IPD due to PCV7 serotypes (-52.7%; 95% CI, -64.2% to -37.5%) and to PCV13 additional serotypes (-55.0% 95% CI, -62.0% to -46.7%) significantly decreased whereas IPD due to non-PCV13 serotypes remained stable (1.0% 95% CI, -12.9% to 17.2%). IPD due to all PCV13 additional serotypes significantly declined with the exception of serotype 3 (-11.3%; 95%CI -35.0% to 21.1%). IPD due to two non-PCV13 serotypes varied: serotype 6C that rose (301.6%; 95%CI, 92.7% to 733.3%, p<0.001), related to the expansion of ST3866C, and serotype 8 that decreased (-34.9%, 95%CI, -57.1 to -1.2, p = 0.049), related to a decline of the ST638. The recombinant clone ST652111A (variant of ST1569V) increased in frequency. The decrease of serotype 19A IPD was linked to a fall in those antibiotic susceptible clones. In the last period, rates of penicillin- and cefotaxime-resistance remained under 10% and 4%, respectively. Adult IPD decreased after the PCV13 introduction in Spain due to herd protection. The spread of multidrug resistant clones (ST3866C, ST652111A) related to non-PCV13 serotypes needs further surveillance.

Highlights

Streptococcus pneumoniae is a leading cause of severe disease worldwide, mainly affecting children and the elderly populations
New emerging serotypes were detected in the late PCV7 period [5,6,7] and the vaccine was improved by including six additional serotypes (PCV13: 1, 3, 5, 6A, 7F, and 19A), whose frequency increased after the PCV7 introduction
The present study demonstrated a herd protection of the adult population in Spain after the PCV13 introduction for children, even when vaccination is mainly due under a private voluntary basis

Summary

Introduction

Streptococcus pneumoniae is a leading cause of severe disease worldwide, mainly affecting children and the elderly populations. Thereafter, the incidence of invasive pneumococcal disease (IPD) dramatically decreased among children due to PCV7-serotypes, and among adults due to herd protection [2,3]. This change was accompanied by a general decline in antibiotic resistance [3,4]. New emerging serotypes were detected in the late PCV7 period [5,6,7] and the vaccine was improved by including six additional serotypes (PCV13: 1, 3, 5, 6A, 7F, and 19A), whose frequency increased after the PCV7 introduction This PCV13 was licensed in Spain in 2010 for children and in 2012 for adults. Children’s vaccination occurs mainly in the private market, with the exception of the Autonomous Community of Madrid, which included universal PCV7 vaccination for children in 2009 (3+1 schedule) that was replaced by PCV13 in June 2010 with a coverage higher than 94% [8]

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